More than 12 million Americans have chronic obstructive pulmonary disease. COPD is a group of progressive lung conditions -- including chronic bronchitis and emphysema -- characterized by airway inflammation, reduced airflow and increased mucus production. Ultimately, people with chronic bronchitis may develop emphysema, which is manifested by destruction of lung tissue and enlargement of the lungs’ air spaces. Due to mucus plugging, air trapping and tissue injury, the lungs of people with COPD are more susceptible to bacterial and viral invasion, which sets the stage for pneumonia.

Colonization Versus Invasion

In up to 50 percent of people with COPD, the lower airways are colonized by bacteria, such as Streptococcus pneumoniae, Hemophilus influenzae and Moraxella catarrhalis. These organisms can trigger pneumonia if they invade the surrounding lung tissue. During an episode of pneumonia, the number of bacteria in your airways may increase, but samples of your mucus may reveal several different bacterial species. Thus, the specific cause of bacterial pneumonia in a person with COPD may not be identifiable. Influenza and other viruses can also cause pneumonia, and these pathogens are not always readily identifiable, either.

Worsening Symptoms

COPD is not a gradual, downward spiral for most patients. Rather, it is punctuated by episodes of worsening symptoms – shortness of breath, increased phlegm, wheezing and cough – that physicians call “exacerbations.” According to a 2003 review in the journal "Respiratory Care," about half of the exacerbations seen in COPD patients are triggered by viral or bacterial infections. Regardless of the cause, exacerbations often lead to an abrupt decline in lung function, much of which may not be recoverable. Thus, reducing the number of exacerbations helps preserve lung function.

Assessment and Management

Not all COPD exacerbations, including those triggered by pneumonia, require hospitalization. The Global Initiative for Chronic Obstructive Lung Disease reports that more than 80 percent of exacerbations can be managed on an outpatient basis. However, people with pneumonia tend to be sicker than those whose exacerbations are triggered by colds or airborne irritants, so you are more likely to be hospitalized if you have pneumonia. Your physician will determine the best approach for you based on the severity of your symptoms, a chest x-ray, your blood oxygen saturation and other tests. If your phlegm has changed color – if it has become green or yellow, rather than clear – your doctor may prescribe antibiotics.

Reducing Risk

COPD can stem from a variety of factors, but cigarette smoking remains the principal cause. Furthermore, people who smoke tend to have higher levels of bacterial colonization in their airways, as do individuals with more severe COPD. Thus, people who have COPD are strongly encouraged to stop smoking to reduce their risk for exacerbations. If your doctor has prescribed medications to control your symptoms, adhering to your treatment plan will help prevent exacerbations, including those caused by pneumonia. If you suddenly have more difficulty breathing, if you develop a fever or if your phlegm becomes more abundant or changes color, contact your physician immediately.

About the Author

Stephen Christensen started writing health-related articles in 1976 and his work has appeared in diverse publications including professional journals, “Birds and Blooms” magazine, poetry anthologies and children's books. He received his medical degree from the University of Utah School of Medicine and completed a three-year residency in family medicine at McKay-Dee Hospital Center in Ogden, Utah.